scholarly journals Rate of evolutionary change in cranial morphology of the marsupial genus Monodelphis is constrained by the availability of additive genetic variation

2015 ◽  
Vol 28 (4) ◽  
pp. 973-985 ◽  
Author(s):  
A. Porto ◽  
H. Sebastião ◽  
S. E. Pavan ◽  
J. L. VandeBerg ◽  
G. Marroig ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Evolutionary Change ◽  
Cranial Morphology ◽  
Additive Genetic Variation

From Phenotype to Genotype And Back Again

2019 ◽  
Author(s):  
J. Richtsmeier ◽  
K.M. Lesciotto
Keyword(s):  
Human Evolution ◽  
Evolutionary Change ◽  
Cranial Morphology ◽  
Phenotypic Trait ◽  
Critical Feature ◽  
Developmental Mechanism ◽  
Experimental Approaches ◽  
Physical Forces ◽  
Collaborative Efforts ◽  
Current Emphasis

Traditionally, anthropologists study evolutionary change throughmorphological analysis of fossils and comparative primate data. For the analysis of the genotypephenotype continuum, the current emphasis on genes is misplaced because genes don’t make structure. Developmental processes make structure through the activity of cells that use instructions specified by genes. A critical mechanism underlying any phenotypic trait is the genetically guided change in developmental events that produce the trait. But even when a developmental mechanism is identified, the links between genetically guided instructions and phenotypic outcome are lengthy, complicated, flexible, and sensitive to physical forces of functioning organs. We use the study of craniofacial phenotypes of craniosynostosis (premature closure of sutures) to demonstrate how patterns produced by the covariation of cranial traits cannot always reveal mechanism. Next we turn to encephalization, a critical feature of human evolution that covaries with cranial phenotypes, and show how experimental approaches can be used to analyze mechanism underlying this well-documented pattern in human evolution. With the realization that no single line of evidence can explain the dramatic changes in cranial morphology that characterize human evolution come fundamental changes in the way we conduct anthropological inquiry - collaborative efforts from scientists with diverse expertise will continue to push the field forward.

scholarly journals Pleiotropy and multilocus polymorphisms.

Genetics ◽  
1992 ◽  
Vol 130 (1) ◽  
pp. 223-227
Author(s):  
A Gimelfarb
Keyword(s):  
Genetic Variation ◽  
Linkage Disequilibrium ◽  
Stabilizing Selection ◽  
Additive Genetic Variation ◽  
Very High

Abstract It is demonstrated that systems of two pleiotropically related characters controlled by additive diallelic loci can maintain under Gaussian stabilizing selection a stable polymorphism in more than two loci. It is also shown that such systems may have multiple stable polymorphic equilibria. Stabilizing selection generates negative linkage disequilibrium, as a result of which the equilibrium phenotypic variances are quite low, even though the level of allelic polymorphisms can be very high. Consequently, large amounts of additive genetic variation can be hidden in populations at equilibrium under stabilizing selection on pleiotropically related characters.

scholarly journals Evolution and evolvability: celebrating Darwin 200

2008 ◽  
Vol 5 (1) ◽  
pp. 44-46 ◽  
Author(s):  
John F.Y Brookfield
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Time Scales ◽  
Evolutionary Change ◽  
Adaptive Mutation ◽  
Genetic Covariances ◽  
The Relationship ◽  
The Way

The concept of ‘evolvability’ is increasingly coming to dominate considerations of evolutionary change. There are, however, a number of different interpretations that have been put on the idea of evolvability, differing in the time scales over which the concept is applied. For some, evolvability characterizes the potential for future adaptive mutation and evolution. Others use evolvability to capture the nature of genetic variation as it exists in populations, particularly in terms of the genetic covariances between traits. In the latter use of the term, the applicability of the idea of evolvability as a measure of population's capacity to respond to natural selection rests on one, but not the only, view of the way in which we should envisage the process of natural selection. Perhaps the most potentially confusing aspects of the concept of evolvability are seen in the relationship between evolvability and robustness.

scholarly journals The genomics of adaptation

2012 ◽  
Vol 279 (1749) ◽  
pp. 5024-5028 ◽  
Author(s):  
Jacek Radwan ◽  
Wiesław Babik
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Royal Society ◽  
Genetic Basis ◽  
Genomic Data ◽  
Evolutionary Change ◽  
Introductory Article ◽  
Technological Advances ◽  
A Genome ◽  
Genome Level

The amount and nature of genetic variation available to natural selection affect the rate, course and outcome of evolution. Consequently, the study of the genetic basis of adaptive evolutionary change has occupied biologists for decades, but progress has been hampered by the lack of resolution and the absence of a genome-level perspective. Technological advances in recent years should now allow us to answer many long-standing questions about the nature of adaptation. The data gathered so far are beginning to challenge some widespread views of the way in which natural selection operates at the genomic level. Papers in this Special Feature of Proceedings of the Royal Society B illustrate various aspects of the broad field of adaptation genomics. This introductory article sets up a context and, on the basis of a few selected examples, discusses how genomic data can advance our understanding of the process of adaptation.

scholarly journals Characterizing the oligogenic architecture of plant growth phenotypes informs genomic selection approaches in a common wheat population

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Noah DeWitt ◽  
Mohammed Guedira ◽  
Edwin Lauer ◽  
J. Paul Murphy ◽  
David Marshall ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Plant Growth ◽  
Genomic Selection ◽  
Plant Height ◽  
Prediction Models ◽  
Growth Traits ◽  
Heading Date ◽  
Additive Genetic Variation ◽  
Moderate Effect ◽  
Over Time

Abstract Background Genetic variation in growth over the course of the season is a major source of grain yield variation in wheat, and for this reason variants controlling heading date and plant height are among the best-characterized in wheat genetics. While the major variants for these traits have been cloned, the importance of these variants in contributing to genetic variation for plant growth over time is not fully understood. Here we develop a biparental population segregating for major variants for both plant height and flowering time to characterize the genetic architecture of the traits and identify additional novel QTL. Results We find that additive genetic variation for both traits is almost entirely associated with major and moderate-effect QTL, including four novel heading date QTL and four novel plant height QTL. FT2 and Vrn-A3 are proposed as candidate genes underlying QTL on chromosomes 3A and 7A, while Rht8 is mapped to chromosome 2D. These mapped QTL also underlie genetic variation in a longitudinal analysis of plant growth over time. The oligogenic architecture of these traits is further demonstrated by the superior trait prediction accuracy of QTL-based prediction models compared to polygenic genomic selection models. Conclusions In a population constructed from two modern wheat cultivars adapted to the southeast U.S., almost all additive genetic variation in plant growth traits is associated with known major variants or novel moderate-effect QTL. Major transgressive segregation was observed in this population despite the similar plant height and heading date characters of the parental lines. This segregation is being driven primarily by a small number of mapped QTL, instead of by many small-effect, undetected QTL. As most breeding populations in the southeast U.S. segregate for known QTL for these traits, genetic variation in plant height and heading date in these populations likely emerges from similar combinations of major and moderate effect QTL. We can make more accurate and cost-effective prediction models by targeted genotyping of key SNPs.

scholarly journals Mhc polymorphisms fail to explain the heritability of phytohaemagglutinin-induced skin swelling in a wild passerine

2009 ◽  
Vol 5 (6) ◽  
pp. 784-787 ◽  
Author(s):  
Camille Bonneaud ◽  
Janet S. Sinsheimer ◽  
Murielle Richard ◽  
Olivier Chastel ◽  
Gabriele Sorci
Keyword(s):  
Genetic Variation ◽  
Immune Responses ◽  
Environmental Effects ◽  
Natural Populations ◽  
Wild Populations ◽  
Genetic Determinants ◽  
House Sparrows ◽  
Additive Genetic Variation ◽  
Significant Heritability ◽  
Mhc Polymorphisms

Genetic estimates of the variability of immune responses are rarely examined in natural populations because of confounding environmental effects. As a result, and because of the difficulty of pinpointing the genetic determinants of immunity, no study has to our knowledge examined the contribution of specific genes to the heritability of an immune response in wild populations. We cross-fostered nestling house sparrows to disrupt the association between genetic and environmental effects and determine the heritability of the response to a classic immunological test, the phytohaemagglutinin (PHA)-induced skin swelling. We detected significant heritability estimates of the response to PHA, of body mass and tarsus length when nestlings were 5 and 10 days old. Variation at Mhc genes, however, did not explain a significant portion of the genetic variation of nestling swelling to PHA. Our results suggest that while PHA-induced swelling is influenced by the nest of origin, the importance of additive genetic variation relative to non-additive genetic variation and the genetic factors that influence the former in wild populations still need to be identified for this trait.

scholarly journals Shared additive genetic variation for alcohol dependence among subjects of African and European ancestry

2017 ◽  
Vol 24 (1) ◽  
pp. 132-144 ◽  
Author(s):  
Leslie A. Brick ◽  
Matthew C. Keller ◽  
Valerie S. Knopik ◽  
John E. McGeary ◽  
Rohan H.C. Palmer
Keyword(s):  
Genetic Variation ◽  
Alcohol Dependence ◽  
European Ancestry ◽  
Additive Genetic Variation

Utilization of heterosis in poultry

1958 ◽  
Vol 9 (4) ◽  
pp. 599 ◽  
Author(s):  
FHW Morley
Keyword(s):  
Body Weight ◽  
Genetic Variation ◽  
Genetic Variability ◽  
Sex Chromosome ◽  
Inbred Lines ◽  
White Leghorn ◽  
Egg Weight ◽  
Additive Genetic Variation ◽  
White Leghorns ◽  
Recessive Genes

Records were analysed of 500-day production, egg weight, 11-week and mature body weight, sex maturity, and broodiness of the crossbred progeny of inbred lines of Australorps mated to White Leghorns, and inbred lines of White Leghorns mated to Australorps. Clear differences between lines of both breeds mere found in most characters, indicating the presence of potentially useful amounts of additive genetic variation. Non-additive genetic variation was also found to be present in varying degrees in different characters. Because of the difficulties of developing and maintaining inbred stocks of poultry, and the importance of sex-linked characteristics in some commercial environments, a scheme is proposed which may enable heterosis to be exploited without the use of inbred material. The basis of this scheme is the combination of the White Leghorn sex chromosome, with varying proportions of Australorp and White Leghorn autosomes, in a new breed. Assuming that the heterosis observed in the F1 is due to elimination of certain biochemical blocks determined by recessive genes, the formation of the new breed should enable the methods of closed flock breeding to be used in material at a higher level of production, and likely to contain more genetic variability, than either parent breed.

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